"Internal error: memory access violation" during simulation

I made and configured my own lathe in NX10. I started to copy the sim11, changed some graphics and adapted what was needed in different cse driver files. When I simulate a serie of operations I defined in NX it runs like a charm (I just get the message "Unidentified Channel Name" when I select "Machine Code Simulate" but it still works, I suppose it's just something in the .mcf that needs to be adjusted).

But when I try to do "Simulate Machine Code File" I just get that internal error message and nothing else happens. I checked my RAM when I try to launch it but nothing seems wrong there, I'm always under 50% of use (I have 8Go of RAM).